The three suspects have been charged with two felony counts of attempted first degree murder, two felony counts of aggravated battery and one misdemeanor count of criminal trespass to a vehicles.
Raekwon Hudson, 18, and the two teens, both 17, were arrested in the 8900 block of South Phillips at around 2:00 p.m. on Friday.
The shooting occurred at about 1:45 p.m. outside Warren Elementary School at East 92nd Street and South Jeffery Avenue, police said, while students were outside enjoying a picnic to celebrate the end of the school year.
The first victim was identified by her family as Dakayla Hart, 13, an eighth grader.
Chicago Police Superintendent Eddie Johnson said several older students had been turned away from after school end-of-the-year events at Warren Elementary and were hanging out down the street when a vehicle approached them and a shooter or shooters opened fire on them.
The older students ran back to the picnic and the gunfire followed them. Johnson said the two girls were unintended victims who were shot by that gunfire.
"I'm telling you, though, this makes me sick. These little kids out here are out here trying to have an end of the year picnic and they get shot?" Johnson said.
Johnson said police have the vehicle involved in the crime and the investigation is ongoing.
Johnson said that while this kind of violence is unusual in Pill Hill, Chicago police resources will be directed into the area for the last two days of school next week in order to reassure residents.
Both girls were transported to Comer Children's Hospital. Mayor Rahm Emanuel visited with the victims and their families shortly before 3:30 p.m. at the hospital, and was visibly upset afterward.
"Those kids were out on the playground enjoying their childhood, enjoying the closing end of a school year, having a barbecue, and these gangbangers are out shooting other gang members without any regard to the consequences. There is no person in Chicago who is not disgusted by that incident. These are our kids. That is a school. That is a playground. And that is a safe sanctuary for our children," Emanuel said. "They deserve their childhood, uninterrupted by a bunch of gangbangers who don't know the difference between a school and a sanctuary."
Police have not yet confirmed the shooters or their intended targets are known gang members. The mayor became angry when asked how the remaining students at the school are doing. Emanuel left the hospital to go to the scene of the shooting and speak to students, parents, teachers and law enforcement there.
"You can only imagine what the trauma is. I haven't been there, but you can only imagine, and I know what I saw here and thank God for the love of parents and the great medical care they have and the love of the teachers and the principal. And I would hope for once when people say enough is enough, that the rest of the criminal justice system, when they're brought there, understands what enough is enough is," he said before he left.